The molecular clock is a scientific technique which presents a means of estimating evolutionary rates and timescales using genetic data. It uses mutation rate of biomolecules when two or more life forms diverged to estimate the time. Answer is B.
I believe the answer would be D, plant. Plant cell walls appear as tiny little boxes that are given their shape by two chemicals: cellulose and lignin. Cellulose is the basic structural component of plant cell walls and is also found in vegetable matter, cotton and wood. High amounts of cellulose are consumed by herbivores, usually with the assistance of bacteria.
Gel electrophoresis separates fragments on the basis of weight and electric charge. Heavier and/or positively charged fragments don't go as far as lighter and/or negatively charged ones.
I pick c. because I really can't see the screen very well.
Rabbits do not have much of en energy reserve